[scikit-learn] Problems with plotting decision regions

[Sebastian Raschka]

Hi, all,
I am having some problems with showing decision regions in 2D if more than 4 classes are present. Really can’t figure out the source of the problem and would really appreciate some help if you have done this before or have any pointer since I am afraid that I am overlooking something really simple here.

I created a gist of 2 simple examples with images attached:

https://gist.github.com/rasbt/6fb65bba38b70e28e60a9842b988cc67

I think it is very likely that it is not a bug in scikit-learn but rather a matplotlib contourf bug? In case it is a bug at all …

Best,
Sebastian